Articles with reduced tendency to corrode



Patented Oct. 6, 1936 UNITED STATES PATENT OFFICE ARTICLES WITH REDUCED TENDENCY -TO CORRODE J Hermann Schulz and Carl Carius, Dortmund, Germany, assignors to the firm Vereinigte Stahlwerke Germany Aktiengesellschaft,

Dusseldorf,

'No Drawing. Driginal application May 31, 1933,

Serial No. 673,792. Divided and this application June 30, 1936, Serial No. 88,266. In Ger:

many May 20, 1932 1 Claim. (Cl. 75-125) prior process is based upon special electrolytic actions .which are thereby caused, that the steel 15 or cast iron is alloyed with copper, antimony, arsenic or tin and in combination with one or several of these additions with magnesium, nickel or aluminum. Said elements are used in the prior process in the following amounts: antimony, arsenic, tin in amounts between'0.0'5 and singly or together, copper in amounts up to 1%, magnesium between 0.1 and 5%, aluminum between 0.05 and 5%.

Further researches have shown that the titanium and vanadium elements act in a similar way as the magnesium and aluminum elements used secondly according to the main patent, and they are not only equivalent to these elements, espe-,-' cially aluminum, but even superior thereto. Since this has been found out, it is possible to replace 30 the aluminum as well as magnesium by titanium or vanadium. The favourable influence of these two elements could not be foreseen either on account of their electrochemical or chemical behaviour.

A further economically advantageously acting influence of titanium and vanadium, owing to which steels alloyed with these elements will ex'cel compared with aluminium containing steels, is that the capacity of steels alloyed with titanium and vanadium of oifering increased resistance to the attacks of water will find expression already a short time after the beginning of corrosion in a considerable reduction of corrodlng speed. For example the corroding speed in sea water will be reduced already after 14 days approximately 20% and in river water about 40% compared with that of copper-nickel steels alloyed withaluminum. Steels according to the inv 50 vention are further distinguished by a perfectly uniform rusting of their surface exposed to the corroding agent. Local corrosions attacks in the form of dents or holes or notch-like depressions, which cause a reduction of the mechanical quali- 55 ties of a steel, do not happen. From the point of view of foundry technics and, metallurgy too, the

' possibility of substituting titanium or vanadium for aluminum afi'ords an advantage in so far as steels mixed with titanium and vanadium can be worked better than those having an addition of aluminum.

The two lements will have the efiect described already at very slight amounts thereof, namely, if both metals together are present in a quantity of 0.1%. Upwardly, the amount of metals with respect to their corrosion-stopping influence is unlimited. However, itis advisable when adding titanium not to exceed 1% and in case of vanadium 0.5%, as a greater addition would not afiord any extra advantages.

Thus the invention comprises articles witha reduced tendency to corrode under the action of a corroding agent, more particularly the moisture contained in water, seawater and moist soil; said articles being made from a ferrometal alloy con taining 0.2-1% copper, titanium between about 0.1 and 1%, vanadium between about 0.1 and 0.5% and in addition nickel in amounts between about 0.2 and 1% and the balance substantially all iron, thealloying elements copper, and nickel forming together with titanium and vanadium a firmly adhering skin on the articles, due to the corroding attack by said corroding agent.

It may be mentioned that the further composition of the alloys besides the elements above specified is the usual one. Thus the alloy may be alloyed for some other reasons with the usual amounts of elements such as for example manganese, silicon, phosphorus, chromium, tungsten, molybdenum, cobalt, boron, zirconium, beryllium, as has been stated in my prior patent and in' the case of steels the accompanying elements may be present in approximately the following amounts:

and in the case of iron in approximately the following amounts:

a Per cent Carbon 2 to 3.6 1 Silicon 0.3 to 3 Manganese Traces up. to 0.12

Phosphorus: Traces up to 1.0

We claim: w nickel in amounts between about 0.2 and 1% and Articles with a reduced tendency to corrode the balance substantially all iron, the alloying under the action of a corroding agent, more parelements copper, and nickel forming together ticularly the moisture contained in water, seawith titanium and vanadium a. firmly adhering water and moist soil; said articles being made skin on the articles, due to the corroding attack 5 from a ferrometal alloy containing 0.2-1% copby said: co roding agent. per, titanium between about 0.1 and 1%, vanadi HERMANN SCHULZ. um between about 0.1 and 0.5% and in addition CARL CARIUS. 

